D because I just took the quiz
This is the Gerund: Gerund is formed by adding -ing to the verb stem: for example: do-ing; mak-ing, kiss-ing.
It can be used as a noun, but also in other positions, but here is an example for the noun use:
Kissing Paul was a good idea.
As feud is to quarrel. The first pair are synonyms that mean mostly the same thing. The trick to questions like that is to figure out the relationship between the given pair to find the best matching pair.
The answer is A because synonymous are similar words the the original word that was given
Tell them it's a great responsibility learning experience